This invention relates to an optical scanning system which scans an original document and converts scanned information into electrical signals and, more specifically, to an optical system which focuses light from a light emitting diode array via a gradient index lens array onto a document scan line.
A variety of prior art scanning systems have been used to scan a document and electronically capture reflected signals therefrom. The signals are then be used to control various types of print mechanisms such as facsimile transceivers and ink jet or thermal recorders. For example U.S. Pat. No. 3,610,824 discloses a facsimile system wherein a document is scanned by a rotating turret scan assembly, the reflected information content being collected and translated into electrical signals by a photosensing element. The signals from the light collector are then used to control operation of a recorder. U.S. Pat. Nos. 4,179,621 and 4,112,469 disclose raster scanning systems which utilize a plurality of solid state sensors to detect scanned information. The sensor array generates signals which can be stored or sent to remote locations to operate appropriate recording devices.
These prior art systems require sophisticated and costly optical components which require large areas for emplacement. The systems also require that the components be arranged along a fairly long optical path adding to the space requirements.
The present invention is directed to a scanning system which is small in size and comparatively simple in construction. The invention relates to an optical scanning system for scanning an original document lying in an object plane and generating electrical signals representative thereof, the system comprising an optical assembly consisting of a light emitting linear array spaced apart from, and parallel to said document, means to selectively activate said light emitting array to produce a band of radiation directed towards said document, a gradient index lens placed between said light emitting array and document, said lens array adapted to focus said illumination band as a narrow scan line on said document, light detecting means adjacent said scanned line to collect reflected light and generate a signal representative of the scanned information and means to produce relative movement between said optical assembly and said document.